1. Field of the Invention
The present invention relates to an improved method of inserting an intra-aortic balloon (hereinafter "IAB") device into the body by a sheathless insertion technique. Additionally, the invention relates to the use of a hemostasis sheath with this technique. When used in combination with the sheathless insertion technique, the hemostasis sheath facilitates use of the IAB device by lowering the degree of the obstruction in the femoral artery while controlling bleeding back through the insertion site after the IAB has been inserted.
2. Description
IAB devices are introduced into the body and are used to assist the pumping action of the heart. See, for example, U.S. Pat. No. 4,362,150. In some instances, they may remain in the body for extended periods of time, such as several days or more.
One method of installing an IAB device in the body is via a non-surgical insertion into the femoral common artery through the skin using the percutaneous insertion (Seldinger) technique.
In the prior art percutaneous insertion technique, the skin is punctured to form a hole through the skin and into the femoral artery. A short guide wire is inserted into the femoral artery and the hole is then expanded by an inserter dilator (for example, an 8-French dilator) which slides over the guide wire through the skin into the artery. The inserter dilator is removed and a series of progressively larger dilators are inserted into the hole over the guide wire to increase the size of the hole. Next an insertion sheath is passed through the hole and into the femoral artery. This sheath has an inside diameter generally corresponding to the outside diameter of the IAB to be inserted. The short guide wire is removed and is replaced by a long guide wire which is fed up through the artery to the vicinity of the aorta. The IAB is passed over the distal end of the guide wire and slides along the long guide wire up through the sheath and along the artery all the way up to the aorta.
Although the foregoing procedure generally is a safe, rapid and efficacious way of intra-aortic balloon insertion, the prerequisite insertion and use of the sheath is a step which requires time and equipment to perform, often under circumstances such that time is a critical factor to patient survival, as during cardiogenic shock.
During the foregoing described procedure, arterial bleeding through the sheath must be carefully controlled during the time interval between the removal of the short guide wire from the sheath and the insertion of the wrapped balloon over the long guide wire. Often, especially in a hypovolemic patient, this loss of blood may be critical. Also when the balloon bladder is wrapped, spiral interstices are produced along its length. The interstices of the wrapped balloon membrane do not provide for the complete occlusion of the sheath between its inner wall and the wrapped balloon. Therefore, a certain amount of arterial bleeding takes place during the time that is required to fully insert the wrapped balloon membrane portion of the balloon catheter into the blood vessel.
In some cases, the sheath may have to be withdrawn partly from the percutaneous wound to permit complete introduction of the balloon membrane into the sheath, especially in those cases of extreme vascular tortuosity. This creates an additional loss of critical time and of critical blood.
Another problem experienced with some patients, is that after IAB insertion is complete, blood flow to the lower extremities is diminished substantially. The decrease in blood flow is generally attributable to the obstruction of the femoral artery caused by the relatively large diameter of the insertion sheath extending into the artery. By removing the sheath, the obstruction in the femoral artery can be decreased substantially. Certain prior art techniques attempts to solve this concern by utilizing splittable insertion sheaths. Various types of splittable, removable insertion sheaths which would be suitable for this purpose are disclosed in the prior art. See for example, U.S. Pat. Nos. 4,166,469, 4,581,019 and 4,581,025. Once the insertion sheath is removed, there would remain the IAB catheter which connects an inflatable and deflatable bladder member of the IAB with the external pumping/monitoring equipment.
U.S. Pat. No. 4,540,404 attempts to address these concerns by using an IAB with a tapered tip and a sheath which slides over the balloon bladder to form an assembly. After insertion, the sheath can be withdrawn to expose the balloon.
However, after removal of the insertion sheath the arterial wall must constrict to seal around the balloon catheter, which has a smaller outside diameter than the insertion sheath. Therefore, in non-elastic or diseased vessels, the required vessel constriction may not always occur resulting in profuse bleeding from the insertion site between the IAB catheter and arterial puncture.
One way to stop this bleeding is to exert pressure on the artery above the insertion site. However, this has the disadvantage that it may damage the balloon catheter and requires time and an additional step in the IAB insertion process. If bleeding cannot be stopped, the IAB must be removed.